Question

An ideal gas, obeying kinetic theory of gases cannot be liquefied, because:

• A. it solidifies before becoming a liquid
• B. forces acting between its molecules are negligible
• C. its critical temperature is above $0^{\circ }C$
• D. its molecules are relatively small in size

Answer 1

Answer: (B)

forces acting between its molecules are negligible

A gas can only be liquefied if some forces of attraction are acting in its molecules. According to kinetic theory, an ideal gas is devoid of the force of attraction in its molecules, therefore it cannot be liquefied.